Roasting furnace



Aug. 30, 1927.

- 1,640,988 H. J. HARTLEY ETAL. ROASTING FURNACE Filed July-21. 1926 I 2 ShQGtS-SIZGGt l I ATTORNEYS 1,640,988 1927' H. J. HARTLEY ET AL RQAS'I'ING FURNACE Filed July 21, 1926 2 sheets heet 2 Ill! III/l/l/l 44 44 g9- INVENTORS flem y if Mrf/qy Edward jaw/fr Dz/J/qy .Bqk'd ATTORNEYS Patented Aug. 30, 1927.

UNITED STATES PATENT OFFICE.

HENRY J. HARTLEY, QF NEW YORK, N. Y. EDWARD J. FOWLER, OF REDWOOD CITY, AND DUDLEY BAIBD, OI BERKELEY, CALIFORNIA, ASSIGNOBS TO NICHOLS COPPER COMPANY, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

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Application filed July 21,

This invention relates to roasting furnaces and more particularly to multiple hearth rotating shaft furnace constructions.

In furnaces of this type difficulty has heretofore been experienced in providing a durable construction of commercial size and yet having its interior parts readily accessible and demountable for inspection, repair or replacement. The furnace construction embodying this invention may comprise a pluralityvof superposed hearths together with a surrounding furnace wall ,which are divided vertically of the furnace to form two separable furnace sections and if desired a carriage may be provided to facilitate the removal of one section, thus allowing the sections to be easily separated for inspection and-cleaning. Also, if desired,

the various hearths, supporting members and other parts within the furnace, may according to this invention be demountable for permitting examination, replacement and cleaning.

Various further specific objects, features and advantages will more clearly appear from the detailed description given below taken in connect-ion with the accompanying drawings which form a pai't of thisv Specification In the drawings,

Fig. 1 represents a veraxis of a furnace construction embodying the invention;

Fig. 2 is a plan view showing the divided furnace wall construction embodying this invention, with the furnace sections in separated position; f

Fig. 3 is an elevational' partsshown in Fig. 2;; u I

Fig. 4 is a horizontalfse'ctional;View of a tionj and 'showfurnace embodying .th e'j' ing a, typical hearth'cons r citilon ,and arrangement; 3 1;

Fig. 5 is an elevational view-sliowing in detail the manner of securing'the hearth supporting arms to' the furnace wall; and

Figs. 6 through 10 illustrate further details of a hearth construction embodying various features of the invention.

furnace vertically spaced or superposed and substantially circulanhearths are designated by the numerals 1116 inclusive. These hearths are tical sectional view taken near-the vertical In the furnace as shown a plurality of' 1928. Serial No. 128,864.

surrounded and supported from a substantlally cylindrical masonry furnace wall 17. The usual rotatable and internally cooled central shaft 18 extends vertically up through the furnace substantially along the central axis thereof and is provided in the usual manner with a series of rabble arms as at 19 and 20 extending radially from the shaft into the space between succeeding hearths. Suitable rabble teeth 21 are provided along each of the rabble arms for advancing the material being treated successively over each of the hearths. A conduit is indicated at 22 for conveying the material to be treated into the furnace through a suitable feeding device as at 23. As shown in the drawing the top of the furnace may be surmounted by support members 24 and a cross member 25. The cross member 25 may serve to hold a central shaft 18 in place and also comprises a support for the feeding device 23. The material entering the feeding device first falls against a feed plate 26 from which it is fed to a delivery bed 27, as by means of a scraper 26 attached to the shaft 18, where it may be given a preliminary heating.

The various features of the furnace construction embodying this invention have been found to be particularly adaptable for use in a furnace for treating silver slime and other semi-liquid ore products and the like. The conduit 22 accordingly provides a suitable means for conveying this material to the furnace. It will be understood, however, that the invention is also adaptable for use with solid products, either finely or coarsely divided. For such ores the conduit 22 would, of course, be replaced by a suitable hopper of any well known construction.

If a semi-liquid ore is being treated, the

bed 27 is gradually advanced to a hopper 29 by the rabble arms as at 1 9'having teeth 21 directed at an angle to deflect the material outwardly from the center of the delivery bed of the hopper 29. The hopper 2 9 may form a part of an ore luted feeding device Comprising a shelf 30, and a scraper 30, which Cooperate with the hopper in. a manner similar to the operation of the feeding arrangementabove described. A sufficient quantity of the semi liquid ore rests upon the feeding plate to close off the feeding device at all times against the exit of furnace gases and still without interrupting'the desired continuous inward flow of ore. The material being treated is scraped or allowed to flow from the shelf 30 and passes down through the furnaceand over each of the successive superposed hearths, alternate hearths being provided respectively with central and peripheral discharge openings as at 31 and 32 so that the ore or other material is gradually advanced inwardly of one hearth toward the central opening and outwardly over the next hearth toward the peripheral opening or openings.

In the treatment of silver slime or other semi-liquid ore products the water content of the product will be gradually driven off on the upper hearths and as the material advances over the lower hearths it will be rapidly calcined or otherwise suitably acted upon under the temperature conditions and in the particular atmosphere present. In treating silver slime this material will be kept from forming into dried cakes because of the continuous rabbling by the rabble arms.

divided state throughout the operation, thus constantly exposing all particles of the product to substantially uniform temperature conditions and to uniform and rapid action by the gases present in the furnace. Accordingly, when the product reaches the lower hearth, it is generally finely divided and uniformly calcined or otherwise treated.

In order to render the interior parts of the furnace readily accessible for inspecttion, repair or replacement and for other purposes, it has been found desirable to divide the furnace vertically so as to form a stationary furnace section 33 (see Figs. 2 and 3), and a removable furnace section 34.

This may be accomplished byconst-ructing the cylindrical furnace wall portion in twoparts, the line of division being substantially along the diameter of the furnace, the

various hearths being similarly divided into two portions which are each supported respectively from the stationary and removable wall section. Each of the wall sections along the line of division maybe provided with flanges as at 35 and 36, which fit together when the furnace sections are in operative position and may be secured in any desired manner as by bolts. The frame parts of the respectivese'ctions of the furnace may be further secured together as by bolts extending through apertures as at 37 and 38 (see Fig. 1), when the furnace sec- The rabble arms will maintain the product in a more or less uniformly finely tions are placed together in their closed operative position. a r As indicated in Fig. 3, the stationary furnace section may be mounted upon. suitable supports 39, whereas the removable section may be provided with a carriage 40 arranged to engage rails 41. A central rotatable shaft carrying the rabble arms and its supporting structure may be preferably associated with the stationary furnace section and operated by a suitable source. of power, such as the rotating shaft 42 whichin turn is operated through suitable speed reducing gearing indicated'at- 43. r

Each of the hearth areas may comprise a plurality of blocks or plates of heat resisting material as at 44, 45 and 46, preferably demountably arranged upon suitable supporting means. In the particular construction illustrated, this'supporting mearis may take the form of radially extending arms as at 47 and 48, (see Fig. 1). As shown in Flg. 5,-these arms may be fittedto the furnace wall with a mortise-and tenon jointcomprising acavity 49 formed in the masonry of the wall and of such dimensions as to fit the end of the supporting arm; In the upon the arms. Fig. 7 is a sectional view showing the cross-sectional form of a typical armsuch as used betweenv two hearth plates 44. The outside edges of the hearth plates may be additionally supported directly from the furnace wall in the manner shown in Fig. 6, which illustrates a corbeled wall portion engaging the rim of a hearth plate 44. The hearth plates maybe formed of any suitable material capable of resisting the high temperatures neccssarywith the particular process for which the furnace is to he used. Cast iron plates are satisfactory for certain installations. whereas in other processing requiring high temperature roasts, it is advisable to use tile plates. The supporting arms may be'formed if necessary of high wardly or outwardly of the furnace. Such interchangeable inclined hearths may be utilized to either promote or retard the flow of material through the furnace as desired. The furnace may be therefore more or less universally used with different ores and materials and the process varied to suit either temporary or permanent requirements without the necessity of rebuilding or redesigning the entire structure.

lVhen the furnace is used in the treatment of silver slimeo'r other valuable ore products, the demountable features of this furnaceare highly desirable, since they facilitatecomplete removal of the ore de osits for inventory purposes without possi ility of waste. Hearth plates as shown may be interchanged with. other hearthplates having ore openings of various other dimensions or arrangements as may be desired for various methods of operating the furnace.

It will be understood that the demountable hearths as above described may be used either with furnaces having solid continuous walls or with furnaces that are separable into sections as here shown. With the sectional construction, it is desirable to providev special means to insure proper engagement of the hearth plates at the line of division of the furnace sections. Fig. 9 is a sectional view at the line of division showing in detail the abutting edges of two hearth plates of suitable construction. The hearth plate 46 for example, may be provided with a depend-' ing lip or flange portion 53 having a beveled edge 54 for engaging and sliding under the lower edge of-the hea-rth plate 45. When the two furnace-sections are in closed or operating position, the hearth plates and 46 will be in the relative positions shown in Fig. 9, thereby insuring a suitable joining of the hearth areas along the line of separation. In order that the hearth plates as at 45 and 46 at each side of the lineof division will be supported in stable condition even when the furnace sections are separated, each of these plates may be made to extend over at least twoof the radial supporting arms as 47 and 47' (see Figs. 4, 7 and 10).

If desired, the adjacent inner ends of each pair of supporting arms may be rigidly held in their proper spaced relation by stay members as at 55 throu h which a securing bolt 56 may extend. (S ee Fig. 8).

The usual practice as followed in the design of furnaces of this general type ma be followed as to constructional details w ich are not specifically referred to herein.

While the invention has been described in detail with respect to certain particular preferred examples which give satisfactory results, it will be understood by those skilled in=the a'rt after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention and it is intended, therefore, in the appended claims to cover all such changes and modifications.

hat is claimed as new and upon which it is desired to secure Letters Patent of the United States is:

1. A multiple" hearth rotary shaft furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall. said hearths and wall being divided vertically of the furnace to form a stationary furnace section and a removable'furnace section, the hearth areas of each section each being made up of a plurality of blocks or plates of heat resisting material supported from the wall sections.

2. A multiple hearth rotary shaft furnace for commercially treating large quantities of ore or the like by a continuous roasting process, comprising a plurality of superposed hearths surrounded by a furnace ,wall, said hearths and wall being divided vertically of the furnace to form a stationary furnace section and a removable furnace section, a carriage for said removable section whereby the sections may be readily separated for inspection and cleaning, the hearth areas of each section each being made up of a plurality of blocks or plates of heat resisting material supported from the wall sections.

3. A multiple hearth rotary shaft furnace construction having a plurality of vertically spaced substantially circular hearths surrounded by a substantially cylindrical furnace wall, said hearths and wall being divided substantially along the vertical axis of the furnace to form two separable furnace sections, whereby the interior may be made accessible for inspection or cleaning, hearth supporting means extending from the walls of each section, and the hearth areas of each section each comprising a plurality of blocks or plates of heat resisting material arranged upon said supporting, means.

4. A multiple hearth rotary shaft furnace construction comprising a plurality of superposed hearths surrounded by a substantially cylindrical furnace wall, each hearth being formed of demountable sectors of heat resisting material supported upon demountable arms extending from said wall.

5. A multiple hearth rotary shaft furnace construction comprising a plurality of superposed hearths surrounded'by a substantially cylindrical furnace wall, eachhearth being formed of demountable sectors of heat resisting material supported by said wall.

6. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, each hearth being divided into at" least two sections demountably secured to said wall.

7. A multiple hearth rotary shaft furnace construction comprising a plurality of superposed hearths surrounded by a substan- "tially cylindrical furnace wall, said hearths and wall being divided vertically of the furnace to form a stationary furnace section and a removable furnace section, the hearth portions of each section being demountable in respect-to the wall portions of their respective sections.

8-. A multiple hearth rotary shaft furnaceconstruction comprising a plurality of superposed hearths surrounded by a substan tially cylindrical furnace wall, said hearths and wall being divided vertically of the furnace to form a stationary furnace section and a removable furnace section, said wall being also formed with a plurality of apertures at each hearth, and hearth supporting arms demountably secured in said apertures.

9. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said wall being formed with apertures adjacent each hearth, hearth supporting arms demountably secured in said apertures, and demountable hearth plates of heat resisting material resting upon said arms.

10. A multiple hearth furnace construction comprising a plurality of superposed hearths surounded by a furnace wall, said wall being formed with apertures adjacent each hearth, hearth supporting arms demountably secured in said apertures, demountable hearth plates of heat resisting material resting upon said arms, and means accessible for release at the exterior of the furnace for securing said arms in position in the furnace wall.

11. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by afurnace wall, said hearths being made up of demountable plates of heat resisting material, and said wall being corbeled at each hearth to provide a rim support for said, plates. I

12. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths being made up of demountable sector shape plates of heat resisting material,

' andsupporting arms of heat resisting material extending substantially radially inwardly from said wall beneath adjacent edges of said plates.

13. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths being made up of demountable sector shaped plates ofheat resisting material, supporting arms of heat resisting material extending substantially radially inwardly from said wall beneath adjacent edges of said plates, and means for securing together at their inner ends adjacent pairs of said arms.

14. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths being made up of demountable plates of-heat resisting material and supporting arms demountably' secured to said wall and extend-ing beneath and between adjacent edges of said plates.

15. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths and wall being divided for forming two separable furnace sections, the hearths being made up of demountable plates of heat resisting material, the hearth plates of one furnace section being formed with depending flanged edges for underlying the corresponding hearth plate edges of the other furnace section along the line of division of the furnace.

16. A multiple hearth furnace construction comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths and wall being divided for forming two separable furnace sections, the hearths being made up of plates of heat resisting material, the hearth plates of one furnace section being formed with means for overlapping and retaining in horizontal alignment therewith the abutting edges of the hearth plates of the other furnace section.

17. A multiple hearth rotating shaft furnace for commercially treating large quan- 1 tities of ore or the like by a continuous roasting process, comprising a plurality of superposed hearths surrounded by a furnace Wall, said hearths and wall being divided vertically of the furnace and forming relatively movable sections, a carriage for at leastone of said sections whereby the sections may be readily separated for inspection and cleaning, the hearth areas of each section comprising blocks or plates of heat resisting material supported from the wall sections.

18. A multiple hearth rotating shaft furnace for commercially treating large quantities of ore or the like, comprising a plurality of superposed hearths surrounded by a furnace wall, said hearths and wall being divided substantially along the vertical axis of the furnace into two relatively. movable sections, the hearth areas of each section comprising demountable blocks or plates of heat resisting material supported from the 

